Tony silvene



(No Model,)

i T.l SILVBNE. Y AUTOMATIG'BRAKE MBGHANISM. No. 536,484.

.Patented Mar. 2.64,* 1895.

.l l Y 4/////// 2. 1

NITED STATES PATE-NT OFFICE. I

TONYSILVENE, OF VICTORIA, CANADA.

AUTOMATIC BRAKE MECHANISM.

SPECIFICATION forming part of Letters Patent No. 536,484, dated March26, 1895. Application iled October 20, 1894:. Serial No. 57261430. (Nomodel.)

To all whom it may concern,.-

Be it known that I, TONY SILvENE, a citizen of France, residing atVictoria, British Columbia, Canada, have invented certain new and usefulImprovements in Automatic Brake Mechanism; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art towhich it appertains tomake. and use the same.

The purpose of the present invention is the provision of a relief valvefor the air cylinders of automatic brake mechanism, which will be selfacting and quickly respond to the variation in pressure of the air inthe train pipe, so as to quickly relieve or bleed the clyinder when itis desired to release the brakes so that the latter will be quick intheir releasing action.

With these ends in view the invention consists essentially of a releasevalve, embodying in its construction two pistons of differential areas,comprising between their oppos, ing ends a chamber which isinncommunication with the train pipe, the smaller piston closing twopassages, the one leading to the brake cylinder, the other to the' outerair.

The improvement consists essentially of the novel features and thecombination of the parts which hereinafter will be more fully describedand claimed and which are shown in the annexed drawing, which is avertical central central section of a valve constructed-in accordancewith and embodying the essential principles of the invention.

The valve case is composed of two parts 2 and 3, which are securedtogether'by bolts or other fastenings, passingthrough the opposingflange ends. The upper part 2, is closed at the outer end, which end iscentrally apertured and internally threaded to receive a set screw, 4.The lower part, 3, is provided with a nipple a, by means of whichcommunication is had with the brake cylinder and with a lateralopening,b, which makes connection with the train pipe, B. The uppervpart of the bore of the part 3 is larger than the lower part of thesaid bore and between the two 'is provided a chamber C, which isaboutopposite the opening, b. Two pistons, E and D, are connected orform part of a valve stem 5, which latter is projected into the chamberformed in. the part 2, and receives a coiled spring 6, which is confinedbetween the pisdton E and a ianged nut 7, held in engagement with theinner end of the set screw 4. The two pistons D and E are in axialyalignment and it steam tight within their respective bores.

The passage 8 is provided in the nipple and communicates with the brakecylinder, but extends vertically through the lower portion of the part 3and communicates with -an annular chamber 9. A relief passage l0 leadsfrom the chamber 9 and is designed to carry off the spent air from thebrake cylinder when it is desired to release the brakes. The piston D isconstructed to close the passages 8 and 10 at the proper time, so as toprevent the escape of the air when the brakes are applied.

The operation ot' the invention is as follows: The opening b, as hereinstated, is connected with a train pipe, the air pressure within which isusually about seventy pounds. The set screw 4 is adjusted to createaforward pressure on the piston E, through the spring 6, of say, abouttwenty pounds. Under normal conditions the upward pressure on the pistonE is about 61.85 pounds and on the piston D, plus the twenty poundspressure of the spring 6, sixty pounds. Hence it will be seen that theupward pressure is in excess of the downward pressure by about 1.85 andtherefore the pistons E and D will occupy the highest position, leavingthe passages 8 and 10, open. On the application of the brakes thepressure in the train pipe is reduced and the upward pressure on thepiston E will be about 53.01 and the downward pressure on the piston D,35.24 plus twenty pounds, the pressure of the spring, or a total of55.24 pounds. It will be seen that the downward pressure exceeds theupward. Hence the'pistons Will move downward and close the passages 8and 10, during the time that the brakes are applied. When the pressurein the train pipe assumes its normal condition the upward pressure willagain exceed the downward pressure and the pistons D and E will quicklyreverse their position and uncover the passages 8 and 10 and permit thebleeding of the brake cylinder.

It will be observed that the valve is wholly munication with the trainpipe, two passages,

the one communicating with the brake cylinder, the other with the outerair and controlled by the smaller of the two pistons, and a springsimilarly exerting a pressure to close the piston and cut off thecommunication between the said two passages, substantially as set forth.

2. The herein shown and described release valve for the cylinders ofautomatic brake mechanism, comprising a valve casing, diierental pistonsoperating in said casing and having a chamber between their opposingends, which is at all times in communication with the train pipe, anannular chamber surrounding the lower portion of the smaller piston andtwo passages extending therefrom, the one adapted to communicate withthe brake cylinder the other leading to the outer air, a coiled springlocated in the upper portion of the Valve casing and surrounding thevalve stem, and a set screw, passing through a threaded opening in theupper end of the valve casing and adapted to regulate the tension of thesaid coiled spring, substantially as described.

In testimony whereof l have signed this specification in the presence oftwo subscribing witnesses.

TONY SILVENE.

Witnesses:

JAS. H. MANSELL, J. CATHCART.

